Skole, the organization’s fourth-best prospect according to Baseball America, impressed during his three weeks in camp, hitting .357 (5-for-14) with three doubles, a homer and five RBI. After missing nearly all of 2013 following a rare Tommy John surgery for a position player, the 24-year-old is expected to open the season at Class AA Harrisburg. A strong year could bring him to Washington by September.

Howell appeared in only two games this spring, going 0-for-2 with a strikeout. The 30-year-old catcher spent last season backing up at Harrisburg and Class AAA Syracuse, hitting a combined .259.

Alfaro, 30, pitched two innings this spring, allowing one run on three hits and striking out three. Signed this winter out of the Mexican League, he’ll likely join the staff in Syracuse to open the season.

Robertson, 26, tossed two scoreless ninth innings for the Nationals this spring and wound up recording saves in both instances. The left-hander had a 3.04 ERA in 26 games with Syracuse last season.